Methods and systems for generating color images of intraoral cavities

ABSTRACT

Systems for generating in-focus color images are provided. Related methods and devices are also provided.

CROSS-REFERENCE

This application is a continuation of U.S. patent application Ser. No.16/921,725, filed Jul. 6, 2020, which is a continuation of U.S. patentapplication Ser. No. 16/505,429, filed Jul. 8, 2019, now U.S. Pat. No.10,716,647, issued Jul. 21, 2020, which is a continuation of U.S. patentapplication Ser. No. 15/925,523, filed Mar. 19, 2018, now U.S. Pat. No.10,363,118, issued Jul. 30, 2019, which is a continuation of U.S. patentapplication Ser. No. 15/175,311, filed Jun. 7, 2016, now U.S. Pat. No.9,956,061, issued May 1, 2018, which is a continuation of U.S. patentapplication Ser. No. 13/957,326, filed Aug. 1, 2013, now U.S. Pat. No.9,393,087, issued Jul. 19, 2016, the entire contents of each are hereinincorporated by reference.

BACKGROUND

Various techniques can be used for obtaining the three dimensional (3D)topography of an object. Information regarding 3D topography of asurface can be used to image a plethora of objects and surfaces. Forexample, 3D topography data can be used for a host of applicationsincluding applications in dental imaging and restoration. In someinstances, 3D imaging methodologies can be used for imaging an oralcavity of a patient. With the additional use of computer-assisted design(CAD) or computer-assisted manufacture (CAM) methods, tooth replacementscan be designed and manufactured without having to make any castimpressions of a patient's teeth. Imaging systems can, e.g., include anoptical probe coupled to a detector and a processor for generating asuitable image to allow for design and fabrication of a desired product(e.g., a physical model and/or prosthesis).

Associating color information with three-dimensional objects is notstraightforward, particularly when the position information is obtainedby using a three dimensional scanning method and the color informationis obtained using a two dimensional scanning method. The problem ofconformally mapping the two dimensional color information onto the threedimensional surface model is difficult and it is common for mismatchingof the color with three-dimensional points to occur. For example, it canbe difficult to accurately associate color information from thedetectors with the correct points on the three dimensional surfacemodel, particularly if relative movement between the object and thedevice occurs between the acquisition of the three-dimensionaltopological data and acquisition of the two-dimensional image data.

Thus, there is a need for improved methods and systems for generatingcolor images, e.g., focused color images, of an object, such as apatient's dentition.

SUMMARY

Systems, methods, and devices for generating color images of an objectare provided. For example, in many embodiments, the systems, methods,and devices generate focused two-dimensional (2D) color images of anobject (e.g., a patient's dentition) in combination withthree-dimensional (3D) topography data of the object. The multi-focalcolor image generation disclosed herein provides enhanced coloracquisition relative to single focal color image generation.Additionally, the systems, methods, and devices disclosed herein can beused to concurrently acquire in-focus color images and corresponding 3Dtopography data.

In some aspects, methods are provided for generating a focused colorimage of an object. The methods can include illuminating the object witha light source, wherein a first wavelength of light and a secondwavelength of light from the light source are focused in a first focalplane and a second focal plane. A detector can be used to collect firstimage data of the illuminated object at a first time point. The firstimage data can correspond to the first wavelength of light reflectedfrom the object at the first focal plane. The same or a differentdetector can also be used to collect second image data of theilluminated object at a second time point. The second image data cancorrespond to the second wavelength of light reflected from the objectat the second focal plane. The first and second image data can then becombined to generate the focused color image of the object. Relatedmethods, systems and devices are also provided.

Other objects and features of the present invention will become apparentby a review of the specification, claims and appended figures.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the features and advantages of the presentinvention can be obtained by reference to the following detaileddescription that sets forth illustrative embodiments, in which theprinciples of the invention are utilized, and the accompanying drawingsof which:

FIG. 1 depicts an example system for generating color and 3D topographyimages, in accordance with an embodiment.

FIG. 2 illustrates an example device for collecting 3D and/or colorimage data, in accordance with an embodiment.

FIG. 3 illustrates an example pattern for color recognition by a colordetector, in accordance with an embodiment.

FIG. 4A shows an example method for generating an in-focus color imageof an object, in accordance with an embodiment.

FIG. 4B illustrates how object locations can be out of focus for aparticular focal length, in accordance with an embodiments.

FIG. 4C illustrates a range of focal lengths employed during focallength scanning, in accordance with an embodiments.

FIG. 4D illustrates focal length differences at time points during focallength scanning that can arise due to chromatic aberration, inaccordance with an embodiment.

FIG. 5, FIG. 6, FIG. 7, and FIG. 8 depict example techniques forscanning and generating 3D and/or color image data of an object, inaccordance with many embodiments.

DETAILED DESCRIPTION

Systems, methods and devices for generating color images of an objectare provided. For example, in many embodiments, systems, methods, and/ordevices generate focused two-dimensional (2D) color images of apatient's dentition in combination with three-dimensional (3D)topography data of the patient's dentition.

The methods and systems provide, among many features, fast and easyacquisition of color and 3D topography data representing an object. Forexample, the methods and systems can be used to collect 2D color imagesthat are in focus and accurately represent an object. In addition, 3Dtopographical data of the surface of the object can be generated inreal-time and in combination with the 2D color image data. In oneaspect, the 3D topographical data and 2D color image data can beprocessed and combined together to be output to a display for uservisualization. Based at least in-part on the methods and systemsdescribed herein, new and improved ways are provided to generatein-focus color images (e.g., RGB images) of an object that can overlaidwith 3D image data corresponding to the object. In existing approaches,in which color imaging and 3D data acquisition are not both performedover a shared period of time, the combined total time required toseparately acquire a color image and separately perform 3D topographyscanning may be longer than desirable with respect to operatorconvenience and/or patient comfort. Additionally, when a hand heldimaging scanner is employed, the acquisition of a color image andperformance of 3D topography scanning is preferably performed at closeto the same time so as to avoid possible detrimental movement of thescanner. In contrast to such existing approaches, the methods andsystems disclosed herein can be used to acquire an color image andperform 3D topography scanning over a shared period of time, therebyreducing the total amount of time required and help avoid detrimentalmovement of the scanner as a result of the reduced total amount of time,as well as a result of the ability to obtain color image data and 3Dtopography data for portions of the object at substantially the sametime.

Any suitable type of object can be imaged. In one embodiment, thescanning methods and systems can be used to generate images representinga patient's teeth. For example, some or all of a patient's teeth can bescanned and provided for display to a user. Using the 3D topographicaldata, for example, 3D virtual models of the patient's teeth can bedisplayed and manipulated, e.g., to facilitate a dental practitioner ina dental procedure. In some instances, e.g., the 3D virtual models canbe used to define spatial relationships of a patient's teeth to definehow to manufacture a dental prosthesis (e.g., a crown or a bridge)shaped to fit that particular patient's occlusion. In addition todisplaying a 3D virtual model, the methods and systems described hereinprovide for display of color information of the patient's teeth. Forexample, gums and teeth can be easily distinguished by color and thatcolor information can also be combined with the 3D topographical data toproduce focused color images that can be combined with the 3Dtopographical data to produce color 3D virtual models. The datagenerated by the systems and methods can also shared and stored to belater transmitted or output, e.g., to manufacturing devices that can beused to make physical models and/or physical replicas of a dentalprosthesis that is designed virtually.

In one aspect, a system is provided for generating a focused color imageof an object. The system can include a polychromatic light source thatcan be used, e.g., to produce light for generating color images. Thepolychromatic light can be reflected off a surface of an object and thenimaged to produce color images. To facilitate production of colorimages, the system can include an optics system optically coupled to thelight source so as to focus the polychromatic light at a first focalplane and a second focal plane, in which the first focal plane includesone color (e.g., red) and the second focal plane includes another color(e.g., green). In some embodiments, a third color (e.g., blue) can befocused at a third focal plane. The focal planes of the different colorsof light can be scanned over the surface of an object and the differentcolors of light can be reflected to allow for collection of color imagedata representing the surface of the object. In some aspects, the systemcan include a detector configured to collect color image data atdifferent time points in a scanning procedure. For example, image datacorresponding to one color (e.g., red) of the polychromatic light sourcecan be collected at a first time point. Image data for another color(e.g., green) can be collected at a second time point. Due in part tothe different Z-locations of focal points for the red and green colors,the green color image data can be in focus while the red color imagedata will not be in focus. As the focal planes are scanned during thescanning procedure, the red focus can be moved such that red image datais in focus and the green is not in focus. The collected image data ofthe focused red and green images can then be processed by a processorconfigured to combine the color image data to generate the focused colorimage of the object.

In some embodiments, focused color images can be produced, e.g., bycollecting in-focus image data of the color data for each color of thepolychromatic light at different time points in which each color isindependently in focus. Given that the different colors can be indifferent focal planes, one color may be in focus while another color isnot in focus because the object will be in the vicinity of one color'sfocal plane but not the other. Depending on the position of thedifferent colors of light in relation to an object (e.g., the focalplanes for each different color), focused image data for one color(e.g., red) can be generated and collected from the object. At that timepoint of collection for the one color, another color (e.g., blue) maynot produce in-focus color data. Instead, focused image data for theother color (e.g., blue) can be collected at a different time point in ascan of the object, such that the other color is in focus and the onecolor (e.g., red) is not in focus. The focused color image data at eachtime point can then be combined to produce an in-focus red and blueimage. Other color combinations can also be used to generate, e.g., realRGB images of an object.

A variety of imaging systems can be used to produce the in-focus colorimages as described herein. An imaging system that produces differentcolors at different focal planes can be used. The different focal planesassociated with the different colors can be scanned over the surface ofan object to generate reflections from the surface. The coloredreflections can be collected and imaged using detectors and thenprocessed to produce in-focus images. The processing can includeselecting different color information at different time points, e.g., inwhich one color is in focus at one time point and another color is infocus at another time point. The in-focus image data for the one colorcan be combined with in-focus image data of the other color, therebyproducing an in-focus image that includes color data for both colors.Similarly, this can be applied to multiple color configurations. Forexample, in-focus image data for red, green and blue images can becombined to form an in-focus RGB image.

In another aspect, a system is provided for generating images of apatient's teeth. The system includes a color detector including atwo-dimensional pixel array that includes: (a) a plurality of firstpixels distributed within the pixel array, (b) a plurality second pixelsdistributed within the pixel array, and (c) a plurality of third pixelsdistributed within the pixel array. Each of the first pixels isconfigured to detect a first wavelength of light reflected from thepatient's teeth. Each of the second pixels is configured to detect asecond wavelength of light reflected from the patient's teeth differentfrom the first wavelength. Each of the third pixels is configured todetect a third wavelength of light reflected from the patient's teethdifferent from the first and second wavelengths. The system furtherincludes a processor operatively coupled to the first pixels, the secondpixels, and the third pixels.

The first, second, and third wavelengths of light can be any suitablecombination of different wavelengths. For example, the first wavelengthcan correspond to red light, the second wavelength can correspond togreen light, and the third wavelength can correspond to blue light.

In many embodiments of the system for generating images of a patient'steeth, the pixel array includes a repeating pattern of the first pixels,the second pixels, and the third pixels. For example, the repeatedpattern can consist of two of the first pixels, one of the secondpixels, and one of the third pixels arranged in a two by two array.

In many embodiments of the system for generating images of a patient'steeth, the processor is configured to process signals received from thefirst pixels, the second pixels, and the third pixels to generate: (a)first image data at a first time point, (b) second image data at asecond time point different from the first time point, and (c) thirdimage data at a third time point different from the first and secondtime points. The first image data is generated in response to signalsfrom the first pixels. The second image data is generated in response tosignals from the second pixels. The third image data is generated inresponse to signals from the third pixels. The processor is configuredto combine the first image data, the second image data, and the thirdimage data to generate a focused color image of the patient's teeth. Theprocessor can also be configured to process signals from the firstpixels, the second pixels, and the third pixels to generate surfacetopology data for the patient's teeth.

Referring to FIG. 1, a scanning system 100 can include a computer system102 having a computer 104 and a display 106. The system 100 can alsoinclude a scanner 108 that can be used to scan an object, e.g., apatient's dentition. The scans can be used, e.g., to generate threedimensional (3D) digital models of an object. The computer system 100can include a microprocessor, memory, or any other suitable hardwareconfigured to process a scanned image of the patient and the devicehaving the coded pattern. The computer system 100 can also include inputmodules such as a keyboard, mouse, and/or tablet. The display 106 (oroutput device) can include a screen or monitor but may also include aprinter, or any other display system. The display of the system, e.g.,can be used to show the generated 3D digital models of an object.

A variety of scanners can be used, e.g., to acquire scan images of anobject, such as a patient's teeth. The scanner 108, for example, can beconfigured to acquire surface topology of structures, e.g., dentalsurfaces of dental structures and/or other tissue surfaces of the faceand head of a patient. In one embodiment, the scanner 108 can be used toacquire scan image data for 3D digital models of at least a portion ofthe patient's teeth. As shown in FIG. 1, the scanner 108 is alsooperatively connected to the computer system 102. The computer system102 can be programmed for reconstructing scanned surfaces from thesurface data provided, to provide a corresponding digital model of thestructure scanned by the scanner. The scanner 108 may also include, forexample, any suitable non-contact scanner, for example an opticalscanner.

In some embodiments, color image data of the intraoral cavity isacquired together with the scan image data to provide a digital modelthat includes 3D digital data representing the surfaces of thestructures as well as color information of the structures scanned, suchas for example of dental surfaces.

The scanning systems can also be used for generating color images and/or3D digital models of all or a portion of an intraoral cavity. In someembodiments, the system can also be configured to scan and generatecolor images and/or 3D digital models of the upper and/or lower arch ofthe patient. In certain embodiments, the system can be configured toscan and generate color images and/or 3D digital models of the upper andlower arches together in occlusion. As described further herein, thecolor images and/or 3D digital models can be used for certain aspects ofthe methods described herein. For example, the color images and/or 3Ddigital models can be used in alignment procedures and/or for generatingphysical models that accurately represent actual positions of thepatient's teeth when the models are mounted in an articulator. The colorimages and/or 3D digital models can include topographical data and/orcolor data representing a variety of dental structures such as one ormore teeth, partial or the full mandibular or maxillary arches, or botharches, and/or details of the spatial relationship between the upper andlower arches in occlusion as well as surrounding tissue, such as gums,and other dental prosthetics (e.g., crowns).

The 3D digital models can be acquired using a variety of suitablemethods. In one embodiment, 3D digital models can be obtained byscanning a patient's intraoral cavity using any suitable equipment forscanning a patient's teeth. Such scanning equipment may include anysuitable optical scanner, for example, the scanner 108 of system 100, asimilar scanner that is not part of the system 100, or a different typeof scanner. In alternative embodiment, the 3D digital models can beobtained from a physical model of the teeth of the particular patient.For example, the surfaces of the physical model can be scanned, or thesurfaces of the impression from which the model was scanned can bescanned to obtain the digital model. In some embodiments, scans can betaken of physical models of a patient's lower arch, upper arch, and thearches in occlusion. Together with a scan of the coded pattern at leasta portion of the patient's teeth, the physical models can then bemodified, e.g., with alignment structures that provide for accuraterepresentation of the patient's occlusion when the models are mounted inan articulator (e.g. holes in the models can have predetermined shapes,sizes and/or orientations for accurate mounting in an articulator). Insome embodiments, a composite positive-negative model can bemanufactured and processed to obtain 3D digitized data. Alternatively,the 3D digitized data may be obtained in any other suitable manner,including other suitable intra oral scanning techniques, based onoptical methods, direct contact methods or any other means, applieddirectly to the patient's dentition or to a physical model thereof.X-ray based, CT-based, MRI-based, or any other type of scanning of thepatient or of a positive and/or negative physical model of theintra-oral cavity can be used, as well. 3D digital models can also beobtained by other ways, such as from an electronic record or anotherpractitioner or scanning facility.

A variety of scanning confocal devices can be used and combined, e.g.,with the methods of generating in-focus color images described furtherherein. Example scanning devices can be found, e.g., in U.S. PublicationNo. US2012/0092678 and WO 00/08415, each of which is incorporated byreference herein. Referring to FIG. 2, an imaging device 200 that can beused for generating 3D topography and color images of an object isillustrated. As shown, a light source 202 for generating a light beamthat can be illuminated through a confocal system 204 configured tosplit the light beam into a plurality of light beams that can, e.g., bedirected through the imaging device and illuminated onto an object,e.g., a surface of a patient's teeth. As shown, the light beams can beoptically coupled to a splitting optic 206 that can be, e.g., abeamsplitter or other optic configured to pass the illuminating lightbeams and redirect light beams that are reflected from the surface ofthe object. In some embodiments, the splitting optic 206 can be adichroic mirror. The arrows in the imaging device of FIG. 2 provideadditional reference for this concept. The imaging device 200 can alsoinclude other optical components, e.g., a lens and/or a mirror that canbe used to direct light in the device. For example, lens 210 can be astatic lens positioned in the imaging device, e.g., so as to allow forfocusing of the reflected light beams onto surface of a detector 208.Other optical components can also be used in the device. For example, adynamic lens 212 can be positioned in the device to allow for scanningof the object through focal planes in space. For purposes of explanationonly, and not to be limiting, the relative dimension of scanning can bealong a Z-axis that is perpendicular to an X-Y plane. The X-Y plane canbe an arbitrary reference plane that can be referenced in relation tothe device and/or the object. The dynamic lens 212 can be used to changethe focal plane of light from the imaging device in relation to, e.g., asurface of an object. As shown by the double arrows in FIG. 2, thedynamic lens 212 can be moved back and forth (short double arrow) in thedevice 200, thereby allowing for scanning of the light illuminated bythe device as indicated by the longer double arrow in the vicinity ofthe focal planes of light generated by the imaging device 200. One ofordinary skill in the art will appreciate the myriad ways to scan lightusing an imaging device, as disclosed herein. For example, the dynamiclens can be coupled to a motor or other mechanism for moving the lens inthe device. A liquid lens, the shape of which can be controllablychanged to controllably change the focal length of the liquid lens, canalso be used.

In some embodiments, the imaging device 200 can include a probe 214 thatis used for scanning an object, as further described herein. The probecan be a handheld probe. In some aspects, the probe can be fullyintegrated along with other components of the imaging device 200, asshown, e.g., in FIG. 2. Other embodiments can include having the probe214 separated from some or all of the other components in imaging device200. For example, the probe 214 may be handheld unit optically coupledto a standing unit that includes, e.g., the light source 202, lenses 210and 212, and the detector 208. In some embodiments, the detector 208 maybe housed in a separate unit from the other optical components and/orthe probe 214. The detector 208 can be a color or monochrome imagesensor, e.g., a CMOS or CCD camera.

In many embodiments, a polychromatic light source 216 is coupled to theimaging device so as to allow for scanning the object with severalcolors of light. Virtually any suitable colors or wavelengths can beused. The polychromatic light source can be used to produce a light beamhaving at least two wavelengths (e.g., a first wavelength and a secondwavelength of light). Any suitable wavelength of light can be used. Aline wavelength of light, such as the light produced by a laser, can beused or broader ranges of wavelengths of light that have a maxwavelength with a spread, such as light produced by a light emittingdiode can also be used. The polychromatic light source generally canoutput wavelengths of light that can allow for collection and generationof color images that can be used to simulate the colors of an object.For example, the wavelengths of light used for imaging can be used toshow color of a patient's reddish gums versus a patient's whitish teeth.

The polychromatic light source 216 can also be coupled (e.g., opticallycoupled) to the rest of the imaging device 200. For example, a whitelight source (e.g., a white LED) can be optically coupled into thedynamic lens 212 so as to allow for focusing of the R, G, and B focalplanes in the vicinity or overlapped with the focal plane of theplurality of light beams produced using the light source 202 and theconfocal system 204. In some embodiments, the polychromatic light sourcecan include a plurality of different wavelength light sources (e.g.,red, green and blue LEDs) that can be arranged in a ring structurearound the dynamic lens 210. In some embodiments, the polychromaticlight source can include a plurality of LEDs (e.g., white LEDs) that canbe arranged in a ring configuration around the dynamic lens 210. Thepositions of the LEDs in the ring can be designed to orient the emittedlight to be coincident with the confocal light beams illuminating thesurface of an object. Furthermore, the polychromatic light source canfurther be integrated into the system to provide homogeneousillumination of the surface of an object using polychromatic light.

In some embodiments, the optics in the imaging device 200 and thecoupling of the polychromatic light source 216 can be configured toproduce different focal planes for different colors of light. Forexample, the focal planes can correspond to red (R), green (G) and blue(B) light that can be used to scan a surface of an object. As shown inFIG. 2, the focal planes for the red light, green light and blue lightcan be at different positions along an axis. For example, an X-Y planehaving red light can be at one position of a Z-axis, an X-Y plane havinggreen light can be at another position of the Z-axis, and an X-Y planehaving blue light can be at another position of the Z-axis.

The relative positions of the different colors at different focal planescan be depend on a variety of factors, such as the color of the light,refractive indices of the optical components, and/or use of optics thatamplify chromatic aberrations that can cause the different colors to befocused at different focal planes. In some aspects, the different focalplanes depending on the color (or wavelength) of light can be generatedusing a variety of techniques. In one embodiment, chromatic aberrationfrom lens or other optics can be used to produce different focal planeshaving different wavelengths of light. In an alternative embodiment,optical components can be provided for each wavelength and arranged togenerate different focal planes for each color. FIG. 2 represents the R,G and B focal points as being separated in an X-Y plane. However, thedifferent R, G and B focal points can be arranged along a Z-dimensionthat is perpendicular to the X-Y plane. It will also be generallyunderstood by one of ordinary skill in the art that the R, G, and Bfocal points can represent planes of red, green and blue light generatedby the imaging device 200. These planes of different colored light canbe scanned over the surface of an object and reflected back into theimaging device 200 and imaged using the detector 208.

As described above, the systems can include components to produce bothcolor image data and 3D topographical data either independently ortogether. The collection of the data can be carried out using a varietyof methodologies. For example, the same or different detectors in thesystem can be used to collect 2D and/or 3D image data. As shown in FIG.2, the same detector 208 can be used to collect reflected light from thepolychromatic light source 216 and the monochromatic light from lightsource 202. As also described, a light beam from light source 202 can besplit into a plurality of light beams that can be transferred opticallythrough the imaging device 200. In some embodiments, the light beam canbe split into an array of light beams that can then be focused in afocal plane that will include an array of focal spots corresponding tothe array of light beams. This array can be used, e.g., for confocalscanning of an object and for imaging the surface of the object toobtain 3D topographical data representing the object's surface. In someembodiments, the array of light beams can be combined such that thelight beams are spatially overlaid with light that is generated by thepolychromatic light source.

In one embodiment, a color detector can be used to collect both thecolor image data associated with the polychromatic light source and the3D topographical data associated with the monochromatic array of lightbeams. For example, the color detector (e.g., detector 208 in FIG. 2)can have a desired pixel pattern for collecting color and 3Dtopographical data. While any suitable pixel array pattern can be used,in a preferred embodiment, the pixel array pattern has a red majoritypixel arrangement, for example, as illustrated in FIG. 3. Thearrangement illustrated in FIG. 3 is a preferred arrangement when acorresponding red wavelength is used as a monochrome topography capturewavelength. In a similar fashion, a blue majority arrangement, where theblue and the red color pixels change position in FIG. 3, is a preferredarrangement when a corresponding blue wavelength is used as a monochrometopography capture wavelength.

FIG. 3 provides an example pattern that is specifically designed tocollect light from the confocal array on predetermined pixels in a colordetector. Other RGB pixels are used, e.g., to collect white orpolychromatic light reflected from the surface of an object beingimaged. As shown in FIG. 3, the pixel pattern has repeating quadrants ofpixels that are sensitive to different colors. Pixels in color sensorcan be fabricated to have a red pixel in the top left and bottom rightquadrant. The pixel in the top right quadrant can be green and the pixelin the bottom left quadrant can be blue. These quadrants can be repeatedthroughout the sensor chip. To provide for simpler and quickercollection of color and topographical data, the bolded red pixels can becoupled with the array of confocal beams such that each confocal beamcan be positioned to illuminate each corresponding red pixel in thepatterned array of pixels. As shown, the array of confocal beams can beconfigured in the system such that each beam illuminates every other redpixel in alternating rows (e.g., row 1 and 3) in the sensor pattern.Accordingly, when 3D topographical scan data is acquired, the pixelpattern will collect 3D topographical scan data from the bolded pixels,but not from other pixels on the surface. The remainder of the pixels,as well as the bolded pixels, can be, however, used to collect colorimage data from the reflected polychromatic (e.g., white) light. As willbe generally understood in the art, the RGB sensitive pixels can beprocessed and used to generate color images of the surface of theobject. Similarly, 3D topographical data of the surface can be processedand used, e.g., to generate 3D virtual models of the surface. With thespecific pattern and known positions of the pixels, color image data and3D topographical data of the surface of an object can be combined andoverlaid together to be displayed, e.g., to a user.

In addition to the devices and systems described herein, methods forgenerating in-focus color images of an object are provided. For example,FIG. 4A illustrates acts of a method 300 for generating an in-focuscolor image of an object. The method 300 includes act 302 through act312, act 320, act 322, and act 326. In a preferred embodiment, themethod 300 includes optional acts 314 through 318 and optional act 324.Also in a preferred embodiment, acts 322 through act 326 are repeatedfor a suitable plurality of image locations. Any suitable imagingsystem, such as any suitable imaging system as described herein can beused to practice the method 300.

In act 302, the object is illuminated with a first wavelength of lightthat is focused to a first wavelength focal length. For example, apolychromatic light source that produces polychromatic light thatincludes light having the first wavelength can be used to illuminate theobject. A monochromatic light source that produces monochromatic lighthaving the first wavelength can also be used to illuminate the object asan alternative. A suitable optics, such as the optics in the system 200illustrated in FIG. 2, can be used to focus the first wavelength to afocal length.

In act 304, the first wavelength focal length is scanned through asuitable plurality of different focal lengths. The range of the focallengths used can be selected to ensure that the imaged portion of theobject is enveloped by the range of focal lengths used. The number offocal lengths used can be selected based on a desired accuracy of focusin the resulting focused color image.

In act 306, image data is generated corresponding to the firstwavelength of light reflected from the object for the plurality ofdifferent first wavelength focal lengths employed. Any suitable imagesensor can be used to generate the image data. For example, a colorimage sensor, such as the detector illustrated in FIG. 3, can be used togenerate the image data. In one embodiment, at least one of the redpixels in each repeating quadrant of four pixels is used to generate asignal in response to the first wavelength of light reflected from theobject that is incident on the red pixel. In many embodiments, the imagedata is obtained for each of the different first wavelength focallengths employed. The image data, however, can be obtained for anysuitable set of the first wavelength focal lengths employed. Forexample, depending on the location in the image, some of the firstwavelength focal lengths may be sufficiently out of focus relative tothe corresponding location on the object such that generating associateddata can be skipped so as to reduce associated data processing. In manyembodiments, the image sensor pixels generate signals indicative of theintensity of the reflected light incident thereon. In many embodiments,the image data includes intensity data for the reflected light incidenton the detector pixels.

In act 308, the object is illuminated with a second wavelength of lightthat is focused to a second wavelength focal length. For example, apolychromatic light source that produces polychromatic light thatincludes light having the second wavelength can be used to illuminatethe object. A monochromatic light source that produces monochromaticlight having the second wavelength can also be used to illuminate theobject as an alternative. A suitable optics, such as the optics in thesystem 200 illustrated in FIG. 2, can be used to focus the secondwavelength to a focal length.

In act 310, the second wavelength focal length is scanned through asuitable plurality of different focal lengths. The range of the focallengths used can be selected to ensure that the imaged portion of theobject is enveloped by the range of focal lengths used. The number offocal lengths used can be selected based on a desired accuracy of focusin the resulting focused color image.

In act 312, image data is generated corresponding to the secondwavelength of light reflected from the object for the plurality ofdifferent second wavelength focal lengths employed. Any suitable imagesensor can be used to generate the image data. For example, a colorimage sensor, such as the detector illustrated in FIG. 3, can be used togenerate the image data. In one embodiment, the green pixel in eachrepeating quadrant of four pixels is used to generate a signal inresponse to the second wavelength of light reflected from the objectthat is incident on the green pixel. In many embodiments, the image datais obtained for each of the different second wavelength focal lengthsemployed. The image data, however, can be obtained for any suitable setof the second wavelength focal lengths employed. For example, dependingon the location in the image, some of the second wavelength focallengths may be sufficiently out of focus relative to the correspondinglocation on the object such that generating associated data can beskipped so as to reduce associated data processing. In many embodiments,the image sensor pixels generate signals indicative of the intensity ofthe reflected light incident thereon. In many embodiments, the imagedata includes intensity data for the reflected light incident on thedetector pixels.

In optional act 314, the object is illuminated with a third wavelengthof light that is focused to a third wavelength focal length. Forexample, a polychromatic light source that produces polychromatic lightthat includes light having the third wavelength can be used toilluminate the object. A monochromatic light source that producesmonochromatic light having the third wavelength can also be used toilluminate the object as an alternative. A suitable optics, such as theoptics in the system 200 illustrated in FIG. 2, can be used to focus thethird wavelength to a focal length.

In optional act 316, the third wavelength focal length is scannedthrough a suitable plurality of different focal lengths. The range ofthe focal lengths used can be selected to ensure that the imaged portionof the object is enveloped by the range of focal lengths used. Thenumber of focal lengths used can be selected based on a desired accuracyof focus in the resulting focused color image.

In optional act 318, image data is generated corresponding to the thirdwavelength of light reflected from the object for the plurality ofdifferent third wavelength focal lengths employed. Any suitable imagesensor can be used to generate the image data. For example, a colorimage sensor, such as the detector illustrated in FIG. 3, can be used togenerate the image data. In one embodiment, the blue pixel in eachrepeating quadrant of four pixels is used to generate a signal inresponse to the third wavelength of light reflected from the object thatis incident on the blue pixel. In many embodiments, the image data isobtained for each of the different third wavelength focal lengthsemployed. The image data, however, can be obtained for any suitable setof the third wavelength focal lengths employed. For example, dependingon the location in the image, some of the third wavelength focal lengthsmay be sufficiently out of focus relative to the corresponding locationon the object such that generating associated data can be skipped so asto reduce associated data processing. In many embodiments, the imagesensor pixels generate signals indicative of the intensity of thereflected light incident thereon. In many embodiments, the image dataincludes intensity data for the reflected light incident on the detectorpixels.

In act 320, one of the first wavelength focal lengths for which thefirst wavelength is focused relative to the object at a respectivelocation is selected. In many embodiments, the selection is based onanalysis of the first wavelength reflected from the object at therespective location. For example, the signals generated by a pixel of adetector indicative of intensity of the first wavelength incidentthereon can be compared to determine which of the first wavelength focallengths provides the highest intensity thereby being indicative of thebest focus relative to the object for the respective location. In act322 and act 324, similar selections are made with respect to the secondand third wavelength focal lengths.

In act 326, image data for the utilized wavelengths (e.g., first,second, and third wavelengths) corresponding to the selected focallengths are combined for the respective location. Accordingly, thecombined imaged data is generated using in-focus data for each of theutilized wavelengths.

Act 322 through act 326 is repeated for other image locations.Accordingly, the resulting focused color image, at least for an objecthaving a non-trivial, non-planar geometry, will typically be generatedusing location dependent focal lengths for each of the utilizedwavelengths, thereby providing for increased image quality relative toimages generated with a single, or non-location dependent focal lengths.

The method 300 can further include additional acts and/or additionaldetails. For example, if a polychromatic light is used or multiplemonochromatic light sources are used, the first, second, and thirdwavelengths can be scanned simultaneously as each type of pixel (e.g.red, green, and blue) in the color image sensor will sense thewavelength of light associated with that pixel. Another alternative isto use a monochrome sensor and use a series of monochrome light sourcesof different colors and perform a separate scan with each color and usethe monochromatic sensor for each color.

Additionally, the first wavelength of light can include a wavelengthbetween about 465 nm and about 485 nm. The second wavelength of lightcan include a wavelength between about 500 nm and about 520 nm. Thethird wavelength of light can include a wavelength between about 640 nmand about 660 nm. The first wavelength image data can include intensityand position data for the first wavelength for each of the plurality offirst wavelength focal lengths or a suitable subset of the firstwavelength focal lengths. The second wavelength image data can includeintensity and position data for the second wavelength for each of theplurality of second wavelength focal lengths or a suitable subset of thesecond wavelength focal lengths. The third wavelength image data caninclude intensity and position data for the third wavelength for each ofthe plurality of third wavelength focal lengths or a suitable subset ofthe third wavelength focal lengths. A white light source can be used toilluminate the object with the first wavelength, the second wavelength,and/or the third wavelength.

The method 300 can also include collecting surface topology data of theobject using a scanning system. For example, the scanning system caninclude a monochromatic light source that is used to illuminate theobject with monochromatic light. A focal length of the monochromaticlight can be scanned through a plurality of different monochromaticlight focal lengths. For each of a plurality of different locations inthe focused color image, one of the monochromatic light focal lengths,for which the monochromatic light is focused relative to the object atthe respective location, can be selected based on analysis of themonochromatic light reflected from the object at the respectivelocation. The surface topology data can be generated based on theselected monochromatic light focal lengths. The surface topology dataand the focused color image of the object can be aligned in a commonframe of reference.

The focal length for each respective wavelength being focused relativeto the object can be selected so as to result in a reduced blur circlediameter relative to existing approaches. For example, in manyembodiments, the focal length for each respective wavelength beingfocused relative to the object is selected to results in a blur circlediameter not greater than 0.4 mm. In an exemplary embodiment, a blurcircle diameter of not greater than 0.4 mm can be achieved by focusingthe respective wavelength within 3.2 mm of the object location beingimaged. As another example, in more closely focused embodiments, thefocal length for each respective wavelength being focused relative tothe object is selected to results in a blur circle diameter not greaterthan 0.2 mm. In an exemplary embodiment, a blur circle diameter of notgreater than 0.2 mm can be achieved by focusing the respectivewavelength within 1.6 mm of the object location being imaged.

The approaches disclosed herein, including methods like method 300, canbe embodied within a suitably configured scanning device. For example,in many embodiments, a scanning device is configured to implement acomputer-implemented method for generating a focused color image of anobject. The computer-implemented method includes processing imagesignals corresponding to a first wavelength of light of a plurality ofdifferent focal lengths that is reflected from the object so as togenerate first wavelength image data. Image signals corresponding to asecond wavelength of light of a plurality of different focal lengthsthat is reflected from the object are processed so as to generate secondwavelength image data. The second wavelength is different from the firstwavelength. For each of a plurality of different locations in thefocused color image, the method includes: (a) selecting one of the firstwavelength focal lengths for which the first wavelength is focusedrelative to the object at the respective location, wherein the selectedfirst wavelength focal lengths for the plurality of different locationsin the focused color image comprise at least two different focallengths; (b) selecting one of the second wavelength focal lengths forwhich the second wavelength is focused relative to the object at therespective location, wherein the selected second wavelength focallengths for the plurality of different locations in the focused colorimage comprise at least two different focal lengths; and (c) combiningthe first wavelength image data corresponding to the selected firstwavelength focal length for the respective location and the secondwavelength image data corresponding to the selected second wavelengthfocal length for the respective location, thereby generating focusedcolor image data for the respective image location for the focused colorimage of the object.

The methods disclosed herein, such as the method 300, can be practicedvia a suitable computer program. For example, in many embodiments, atangible medium is used to store non-transitory computer readableinstructions, that when executed by an imaging system comprising one ormore processors, cause the imaging system to perform any suitable methoddisclosed herein.

In accordance with many embodiments, FIGS. 4B through 4D illustrateaspects of generating a focused color image of an object. As illustratedin FIG. 4B, a three-dimensional object 350 includes an external surface352 that is disposed over a range of distances from a scanner 108 usedto generate an image of the object 350. As a result, at least a portionof the external surface 352 will be out of focus for any particularfocal length employed by the scanner 108. For example, while a firstlocation 354 on the external surface will be in focus when a first focallength 356 is employed, second and third locations 358, 360 on theexternal surface 352 will be out of focus. Likewise, the second location358 will be in focus when a second focal length 362 is employed, but thefirst and third locations 354, 360 will not be in focus. The thirdlocation 360 will be in focus when a third focal length 364 is employed,while the first and second locations 354, 358 will then be out of focus.

In many embodiments, image data for a plurality of focal lengths isobtained for use in generating a focused color image. The plurality offocal lengths is obtained by scanning the focal length of each of thewavelengths (e.g., red, green, and blue) employed. FIG. 4C illustrates aplurality of focal lengths 366, the limits of which extend above andbelow the external surface 352 of the object 350. Because the image dataincludes a plurality of focal lengths, a focal length for a respectiveimage location, which corresponds to a respective location on theexternal surface 352, can be selected so that the respective location onthe external surface 352 is in focus. Any suitable approach can be usedto select focal lengths for which the respective location on the objectis in focus for each of the wavelengths used to construct the in-focuscolor image. For example, light reflected from the respective objectlocation for a plurality of candidate focal lengths can be analyzed todetermine which of the candidate focal lengths corresponds to the bestfocus of the light relative to the respective object location. In manyembodiments, the light reflected from the respective object location isanalyzed to identify which of the candidate focal lengths results inmaximum intensity of the reflected light. Alternatively, the in-focussituation can be inferred from the high spatial frequency contents of animage portion of the said wavelength. Higher frequency contents indicatebetter focus proximity. One or more of the wavelengths can be analyzedto determine the distance to the respective object location. Thedetermined distance can then be used for adjacent scan frames where thetime between frames is sufficiently small to preclude a significantrelative movement between the scanning device and the object beingimaged.

In many embodiments, in-focus image data for each object location isgenerated by combining the in-focus color data for the object location.The in-focus image data for each object location can then be combined togenerate an overall in focus color image for the object.

FIG. 4D illustrates chromatic aberration induced variation in focallengths. When a polychromatic light source is employed, chromaticaberration in the optics can result in the first, second, and thirdwavelengths having different focal lengths at a given point in time. Forexample, at a starting point in time during focal length scanning, acorresponding starting blue focal length 368 can be disposed above acorresponding starting green focal length 370, which can be disposedabove a corresponding starting red focal length 372. Likewise, at alater point in time of focal length scanning, a corresponding blue focallength 374 is similarly disposed above a corresponding green focallength 376, which is disposed above a corresponding red focal length378. In many embodiments, such differences between the focal lengths ofthe wavelengths employed is accounted for when determining whichlocation dependent image data subsets to combine for each of therespective image locations so as to generate the resulting focused colorimage.

In one aspect, an imaging device or scanner can be positioned near anobject (e.g., in a patient's mouth near the patient's teeth). Thescanner can be configured to generate both an in-focus color image and3D topography data. For example, in many embodiments, a scanner employspolychromatic light for color imaging and monochromatic light for 3Dtopographical imaging. The light for each imaging mode can be focused toa focal length. For example, a blue focal length, a green focal length,and a red focal length can be disposed along a Z-dimension (as shown,e.g., in FIG. 5). A focal length associated with light employed for 3Dimaging can also be produced by the scanner. The scanner can scan thefocal lengths up and down in the Z-dimension and collect 3D and colorimage data for the various focal lengths employed. To image a region ofan object, the scanner can be held over the region and the focal lengthscan be scanned in the Z-dimension over time (e.g., over a time span onthe order of milliseconds). During the scanning of the focal lengths,the scanner can be held in a stable position over the object and thefocal lengths can be scanned in the Z-dimension. During an up-scanningof the focal lengths, a down-scanning of the focal lengths, or both,color image data and/or 3D topographical data can be collected for theregion of the object. After scanning of the focal lengths for the regionof the object is complete, the collected color image data and/or 3Dtopographical data can be processed by a computer system and, e.g.,output for visual display. A user holding the device can then move theimaging region to another section of the object (e.g., another sectionof a patient's teeth) and then acquire additional color andtopographical data to then be processed and output to the display. Thisprocess can be repeated until an object is completely scanned. The imagedata from each region of the object can be combined (e.g., using methodsfor generating a focused color image described herein) to render a fullfocused color image of the object. For example, a full image of apatient's teeth can be generated to include both 3D topography of thepatient's teeth and associated focused color image data of the patient'steeth, gums, or other colored material in the patient's mouth.

As described herein, improved methods and systems are provided forgenerating color images of an object, including a variety of methods forgenerating a focused color image of an object. In some embodiments, afirst wavelength of light can have a wavelength between about 465 nm andabout 485 nm, a second wavelength of light can have a wavelength betweenabout 500 nm and about 520 nm, and a third wavelength of light can havea wavelength between about 640 nm and about 660 nm. Other wavelengthscan also be used and configured for a particular application and/ordetector being used. For example, a cyan-magenta-yellow (CMY) colorscheme can be used, or a red-green-blue (RGB) color scheme can be used.

In many embodiments, white light is used to illuminate the object forwhich the focused color image is generated, a red-green-blue (RGB) colorsensor is used to generate image signals in response to the lightreflected from the object, and low dispersed optics are used to deploythe different wavelengths of the white light into different focalplanes. And in many presently preferred embodiments, the opticaldispersion is designed such that the distance between the red focalplane and the green focal plane is equal to the distance between thegreen focal plane and the blue focal plane. For example, the opticaldispersion can be designed such that when the red wavelength focal planeis located at a reference z-dimension (Z0), the green wavelength focalplane is at the reference z-dimension plus a selected delta-z distance(Z0+ΔZ) and the blue wavelength focal plane is at the referencez-dimension plus two times the selected delta-z distance (Z0+2AZ). Byscanning the focal lengths in a stepwise fashion with each step equal tothe selected delta-z distance (ΔZ) between acquisition of color imagedata, the elemental color data (e.g., red data, green data, and bluedata) for three adjacent color image scan frames can be combined togenerate in-focus color data for a particular object location. FIGS. 5,6, 7 and 8 illustrate scanning approaches that can be used inconjunction with an optical system having dispersion that is designedsuch that the distance between the red focal plane and the green focalplane is equal to the distance between the green focal plane and theblue focal plane. While the scanning approaches illustrated in FIGS. 5,6, 7, and 8 can be used in conjunction with an optical system havingdispersion that is designed such that the distance between the red focalplane and the green focal plane is equal to the distance between thegreen focal plane and the blue focal plane, any suitable optical systemcan be used, including optical systems that do not have dispersion thatis designed such that the distance between the red focal plane and thegreen focal plane is equal to the distance between the green focal planeand the blue focal plane. For example, the approaches disclosed hereinfor generating an in-focus color image can be used in conjunction withan optical system having dispersion such that the distance between thered focal plane and the green focal plane is not equal to the distancebetween the green focal plane and the blue focal plane. As anotherexample, the approaches disclosed herein for generating an in-focuscolor image can be used in conjunction with an optical system configuredsuch that the red focal plane, the green focal plane, and/or the bluefocal plane are substantially coincident for any particular scan frame.

FIG. 5 illustrates an approach for obtaining both in-focus color imagedata and surface topography data during focal length scanning. As shown,focal lengths of the respective wavelengths can be scanned over adistance along a Z-dimension in an interval of time. For example, thefocal lengths can be scanned over a range of millimeters or centimetersor more depending on the scale of surface features of an object. FIG. 5shows scanning over a range of tens to hundreds of millimeters (e.g., asshown, about 10-20 millimeters). The time frame for the scanning canalso be on the order of microseconds, milliseconds, or longer. A fullscan time for scanning an object can depend, e.g., on the amount of areaand/or number of Z-scans used for generating an image. In FIGS. 5through 8, the time axis is in milliseconds.

In many embodiments, the scanner collects data used for generating afocused color image of the imaged object and/or 3D topographical datarepresenting the imaged object. In the embodiment illustrated in FIG. 5,the scanned object is illuminated with polychromatic light (e.g., whitelight) at varied time points during scanning of the focal lengths alongthe Z-direction. In FIG. 5, each time point with white illumination isillustrated with the B, G, and R boxes. The focal lengths for the blue,green, and red light from the white light source can be arranged indifferent Z-positions, e.g., by tailoring the chromatic aberration ofthe scanner's optics. The focal lengths of the red, green, and bluelight are varied during the scan. Image data can be acquired for each ofthe focal lengths during the scan. Once in-focus image data is acquiredfor the respective image locations for each color wavelength employed(e.g., red, green, and blue), the in-focus color data for the respectivelocation can be combined to generate in-focus color data for therespective image location. The in-focus color data for all therespective locations can then be combined to generate an overall infocus color image for the object.

In many embodiments that employ wavelength dependent focal lengths, forexample, due to chromatic aberration, the in-focus color image data(e.g., red, green, and blue in-focus image data) that are combined togenerate in-focus image data for a particular object location areobtained at different times. For example, referring to FIG. 5, when aparticular object location is in focus at a first time point T1 relativeto an employed blue wavelength (blue focal position 382), the particularobject location is out of focus relative to employed green and redwavelengths (green focal position 384 and red focal position 386). At asecond time point T2, the particular object location is in focusrelative to the green wavelength employed (green focal position 388)while being out of focus relative to the employed blue and redwavelengths (blue focal position 390 and red focal position 392). At athird time point T3, the particular object location is in focus relativeto the red wavelength employed (red focal position 394) while being outof focus relative to the employed blue and green wavelengths (blue focalposition 396 and green focal position 398). In such a scenario, the blueimage data for the particular object location from the first time pointT1 (blue focal position 382) can be combined with the green image datafor the particular object location from the second time point T2 (greenfocal position 388) and the red image data for the particular objectlocation from the third time point T3 (red focal position 394) togenerate in-focus color image data for the particular object location.Combination of the image data can, e.g., be carried out using thecomputer system and processor as described further herein.

In a similar fashion, different object locations with significantlydifferent distance from the scanner will have different in-focus focallengths. Accordingly, the in-focus color data for such differentlocations will be obtained at different time points during scanning ofthe focal lengths.

As shown in FIG. 5, 3D topography data for the object can be obtainedduring scanning of the focal lengths at time points between the timepoints at which the in-focus color image data is obtained. For example,between time point I and time point II in FIG. 5, 3D topography data canbe obtained by illuminating the object with monochromatic light in theform of an array of separate beams that are each focused to a focallength. In many embodiments, the focal length of the separatemonochromatic beams are incrementally scanned through a plurality ofdifferent focal lengths and image data for each of the beams is obtainedfor each focal length. Similar 3D topography can be obtained betweentime point II and time point III, between time point III and time pointW. The image data for each of the beams can then be analyzed to identifywhich focal length results in maximum intensity of the reflection of therespective beam from the object surface, thereby being indicative of thelocation of the best focus of each beam relative to the object surface,which indicates the distance between the scanner and the object surfacefor the object location from which each beam is reflected.

The color image data can be collected at suitable time points duringscanning of an object surface. For example, 3D topographical data can becollected through both the up and down scans and either entirely orpartially throughout the scans, as well. FIG. 6, for example, shows acombination method of collecting both color 2D image data and 3Dtopographical data during scanning of an object. As shown, color RGBimage data can be generated at time points during focal length scanningalong a Z-dimension. In focus color data for a particular objectlocation can be generated, e.g., by combining the color image data fromdifferent time points in the scan, in which each color, e.g., RGB, arein focus relative to the particular object location at their respectivetimes. Shown in FIG. 6, the 3D topographical data and the color imagedata can be collected during both the ups and downs of the focal lengthscanning procedure. As another example, as shown in FIG. 7, the colorimage data can be collected on both the up scan and the down scan andthe 3D topography data collected only during the up scan.

As described above, the systems can include both imaging optics for 3Dconfocal imaging as well as 2D color imaging. FIG. 6 depicts an examplescanning protocol that can involve staggered collection and/orgeneration of both color and 3D topographical data of an object. Asshown, color image data (e.g., RGB data) can be collected, followed bycollection of 3D topographical data of the surface of the object,followed by color image data (e.g., RGB data), and so on. Anycombination of collecting color image data and/or 3D topographical datacan be employed. For example, 3D topographical data can be collectedduring suitable time periods and used to generate 3D virtual models ofthe object, and 2D color image data can be collected during suitabletime periods other than those used to collect 3D topographical data. Thescanning time used for collecting 3D topographical data can besignificantly longer than the time used to collect 2D color image data,for example, 5 times longer, 10 times longer, or 20 or more timeslonger. Longer multiples, shorter multiples, or any multiples in betweencan be used.

As shown in FIG. 8, the collection of 3D topographical data can beperformed during the up scan, and 2D color image data collected duringthe down scan. As shown, the 2D color image data and the 3Dtopographical data can be collected independently. It is also envisionedthat any of the embodiments described herein, e.g., in FIGS. 5-8, aswell as other combinations can be used at anytime during a focal lengthscanning procedure. For example, some of the ups and downs of the scansduring a focal length scanning procedure can include both collection ofthe 2D color image data and the 3D topographical data. Some of the scanscould include collecting the 2D color image data and the 3Dtopographical data independently.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A system for scanning intraoral cavities,comprising: one or more light source configured to produce lightcomprising a first wavelength and a second wavelength; an optics systemoptically coupled to the one or more light source and configured tofocus the light through a probe onto an intraoral object, wherein saidoptics system is to focus the first and second wavelengths of the lightto different focal lengths; one or more detector configured to collectimage data of the intraoral object for the light comprising the firstwavelength and the second wavelength; and a processor configured togenerate focused color image data for a portion of the intraoral objectbased on the image data associated with the first and second wavelengthsof the light.
 2. The system of claim 1, wherein generating the focusedcolor image data comprises: determining, for each of the first andsecond wavelengths, first and second focal lengths at which therespective first and second wavelengths are focused relative to theportion of the intraoral object; and combining the image data for eachof the first and second wavelengths at the determined respective focallengths, thereby generating the focused color image data for the portionof the intraoral object.
 3. The system of claim 2, wherein: the light ispolychromatic light that further comprises a third wavelength focused bythe optics system to a different focal length than the first and secondwavelengths; and to generate the focused color image data, the processoris further to: determine a third focal length at which the thirdwavelength is focused for the portion of the intraoral object; andcombine the image data for each of the first, second, and thirdwavelengths at the determined respective focal lengths, therebygenerating the focused color image data for the portion of the intraoralobject.
 4. The system of claim 1, wherein the light is polychromaticlight that comprises a first wavelength range including the firstwavelength and a second wavelength range including the secondwavelength.
 5. The system of claim 4, wherein the first wavelength rangeand the second wavelength range are each selected from a groupconsisting of: a wavelength range of between about 65 nm and about 485nm, a wavelength range of between about 500 nm and about 520 nm, and awavelength range of between about 640 nm and about 660 nm.
 6. The systemof claim 4, wherein the polychromatic light further comprises a thirdwavelength range.
 7. The system of claim 1, wherein the one or morelight source illuminates the intraoral object with the first and secondwavelengths simultaneously.
 8. The system of claim 1, wherein theprocessor is further to add the focused color image data to athree-dimensional (3D) digital model of the intraoral object.
 9. Thesystem of claim 8, further comprising: a second light source configuredto produce additional light; wherein the optics system is furtherconfigured to focus the additional light through the probe onto theintraoral object; wherein the one or more detector are furtherconfigured to collect additional image data of the intraoral object forthe additional light, the additional image data comprising depthinformation; and wherein the processor is further configured to generatethe 3D digital model of the intraoral object based on the additionalimage data.
 10. A method of scanning an intraoral cavity, comprising:generating light from one or more light source, the light comprising afirst wavelength and a second wavelength; focusing the light through aprobe onto an intraoral object, wherein the first and second wavelengthof the light are focused to different focal lengths; collecting imagedata of the intraoral object from the light comprising the firstwavelength and the second wavelength with one or more detector; andgenerating focused color image data for at least a portion of theintraoral object based on the image data associated with the first andsecond wavelengths of the light.
 11. The method of claim 10, whereingenerating the focused color image data comprises: determining, for eachof the first and second wavelengths, first and second focal lengths atwhich the respective first and second wavelengths are focused relativeto the portion of the intraoral object; and combining the image data foreach of the first and second wavelengths at the determined respectivefocal lengths, thereby generating the focused color image data for theportion of the intraoral object.
 12. The method of claim 11, wherein:the light is polychromatic light that further comprises a thirdwavelength focused to a different focal length than the first and secondwavelengths, and generating the focused color image data furthercomprises: determining a third focal length at which the thirdwavelength is focused for the portion of the intraoral object; andcombining the image data for each of the first, second, and thirdwavelengths at the determined respective focal lengths, therebygenerating the focused color image data for the portion of the intraoralobject.
 13. The method of claim 12, wherein the polychromatic lightcomprises a first wavelength range including the first wavelength and asecond wavelength range including the second wavelength.
 14. The methodof claim 13, wherein the first wavelength range and the secondwavelength range are each selected from a group consisting of: awavelength range of between about 65 nm and about 485 nm, a wavelengthrange of between about 500 nm and about 520 nm, and a wavelength rangeof between about 640 nm and about 660 nm.
 15. The method of claim 13,wherein the polychromatic light further comprises a third wavelengthrange.
 16. The method of claim 10, wherein the light source illuminatesthe intraoral object with the first and second wavelengthssimultaneously.
 17. The method of claim 10, further comprising: addingthe focused color image data to a three-dimensional (3D) digital modelof the intraoral object.
 18. The method of claim 17, further comprising:generating additional light from an additional light source; focusingthe additional light through the probe onto the intraoral object;collecting additional image data of the intraoral object for theadditional light, the additional image data comprising depthinformation; and generating the 3D digital model of the intraoral objectbased on the additional image data.
 19. A handheld scanner for scanningintraoral cavities, comprising: a probe; a light source that produceslight comprising first and second wavelengths; an optics systemoptically coupled to the light source and configured to focus the lightthrough the probe onto an intraoral object, wherein said optics systemis to focus the first and second wavelengths of the light to differentfocal lengths; and a detector configured to collect image data of theintraoral object for the light, wherein the first and second wavelengthsof the light are usable to generate focused color image data for atleast a portion of the intraoral object.
 20. The handheld scanner ofclaim 19, wherein the light is polychromatic light that comprises afirst wavelength range including the first wavelength, a secondwavelength range including the second wavelength, and a third wavelengthrange including a third wavelength, wherein the first wavelength rangeis between about 65 nm and about 485 nm, wherein the second wavelengthrange is between about 500 nm and about 520 nm, and wherein the thirdwavelength range is between about 640 nm and about 660 nm.